我的第一个接口

Servlet的使用

通过IDEA新建Sevlet工程：

Java -> Web Application （选上”create web.xml”），即可得如下目录结构：

在src中创建继承于HttpServlet的类，重写doGet和doPost方法：

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class SeatOverrMain extends HttpServlet {
    public SeatOverrMain() {
        super();
    }
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletOutputStream out=resp.getOutputStream();
        resp.setContentType("text/plain");
        resp.setCharacterEncoding("UTF-8");
        String param=req.getParameter("Seat");
        if(param.equals("Seat")){
            out.print("Success");
        }else{
            out.print("fail");
        }
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req,resp);
    }
}

注意要将doGet和doPost方法中的super语句去掉，不然访问时会报405错误

HttpServlet所在的jar包为：“servlet-api-6.0.41.jar”，可在jar search中获得

然后需要搭建Tomcat服务器，步骤如下：

先下载Tomcat的压缩包解压出来，在IDEA运行按钮处打开Edit Configuration窗体：

Defauts -> Tomcat Server -> Local -> server -> Configure…

在Toncat Home中选中刚刚解压出来的Tomcat文件夹，回到Edit Configuration窗体：

Defauts所在栏中会多出一个Tomcat Server，选中然后在右边窗体中选择Deployment：

再添加[项目名]:war exploded，然后ok。在刚刚运行处便会出现Tomcat图标此时即可运行

Spring Boot

很牛逼的一个框架，刚开始被她的简单惊到了，O O

具体用法参见：

构建微服务：Spring boot 入门篇

跨域访问

需要新建过滤类：

package io.github.grooters.seatOccupied.filter;
import org.springframework.stereotype.Component;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@Component
public class CorsFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest reqs = (HttpServletRequest) servletRequest;
        response.setHeader("Access-Control-Allow-Origin","*");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, PATCH, DELETE, PUT");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        filterChain.doFilter(reqs, response);
    }
    @Override
    public void destroy() {}
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {}
}

返回界面

添加依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

application.properties中添加配置：

# 定位模板的目录,在resouces/static中
spring.mvc.view.prefix=/
# 给返回的页面添加后缀名
spring.mvc.view.suffix=.html

Controller：

package io.github.grooters.seatOccupied.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
@Controller
public class Index {
    @GetMapping("/index")
    public String greet() {
        return "index";
    }
}